/*
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 * and the project initiators Erik Lindahl, Berk Hess and David van der Spoel.
 * Consult the AUTHORS/COPYING files and https://www.gromacs.org for details.
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/*! \file
 * \brief
 * Declares \c t_pargs, parse_common_args() and related methods.
 *
 * \inpublicapi
 * \ingroup module_commandline
 */
#ifndef GMX_COMMANDLINE_PARGS_H
#define GMX_COMMANDLINE_PARGS_H

#include <cstdint>

#include "gromacs/commandline/filenm.h"
#include "gromacs/fileio/oenv.h"
#include "gromacs/math/vectypes.h"
#include "gromacs/utility/basedefinitions.h"
#include "gromacs/utility/real.h"

struct gmx_output_env_t;

/*! \addtogroup module_commandline
 * \{
 */

/** Command line argument type. */
enum
{
    etINT,
    etINT64,
    etREAL,
    etTIME,
    etSTR,
    etBOOL,
    etRVEC,
    etENUM,
    etNR
};

/*! \brief
 * Command-line argument definition for C code.
 *
 * \inpublicapi
 */
typedef struct
{
    /** Name of the argument (with leading dash included). */
    const char* option;
    /** Whether the argument is set (should be initialized to `FALSE`). */
    gmx_bool bSet;
    /** Type of the argument (one of the enums in pargs.h). */
    int type;
    /*! \brief
     * Pointer to variable that is to receive the value.
     *
     * The expected type depends on the value of \a type.
     * If an argument is not set by the user, then the pointed value is not
     * changed.  In other words, the initial value for the variable defines the
     * default value.
     */
    union
    {
        /*! \brief
         * Generic pointer for operations that do not need type information.
         *
         * Needs to be the first member to use initialized arrays.
         */
        void* v;
        /** Integer value for etINT. */
        int* i;
        /** Integer value for etINT64. */
        int64_t* is;
        /** Real value for etREAL and etTIME. */
        real* r;
        /*! \brief
         * String value for etSTR and etENUM.
         *
         * For etSTR, this should point to a `const char *` variable, which
         * will receive a pointer to the string value (caller should not free
         * the string).
         *
         * For etENUM, this should be an array of `const char *` values, where
         * the first and last values are `NULL`, and the other values define
         * the allowed enum values.  The first non-NULL value is the default
         * value.  After the arguments are parsed, the first element in the array
         * points to the selected enum value (pointers will be equal).
         */
        const char** c;
        /** Boolean value for etBOOL. */
        bool* b;
        /** Vector value for etRVEC. */
        rvec* rv;
    } u;
    /*! \brief
     * Description for the argument.
     *
     * If the string starts with `HIDDEN`, then the argument is hidden from
     * normal help listing and shell completions.
     */
    const char* desc;
} t_pargs;

/*! \brief
 * Returns ordinal number for an etENUM argument.
 *
 * \param[in] enumc  Array passed to `t_pargs` for an etENUM argument.
 * \returns   Index of selected enum value in the array.
 *
 * See t_pargs::u::c for the expected format of the array, including how the
 * first element should be initialized.
 * Note that the return value starts at one instead of zero: if the first enum
 * value is selected, this returns 1.
 */
int nenum(const char* const enumc[]);

/*! \brief
 * Returns value of an etINT option.
 *
 * \param[in] option Name of etINT argument to query.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   Value of \p option.
 *
 * \p option must specify a valid argument in \p pa of the correct type.
 */
int opt2parg_int(const char* option, int nparg, t_pargs pa[]);

/*! \brief
 * Returns value of an etBOOL option.
 *
 * \param[in] option Name of etBOOL argument to query.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   Value of \p option.
 *
 * \p option must specify a valid argument in \p pa of the correct type.
 */
bool opt2parg_bool(const char* option, int nparg, t_pargs pa[]);

/*! \brief
 * Returns value of an etREAL/etTIME option.
 *
 * \param[in] option Name of etREAL/etTIME argument to query.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   Value of \p option.
 *
 * \p option must specify a valid argument in \p pa of the correct type.
 */
real opt2parg_real(const char* option, int nparg, t_pargs pa[]);

/*! \brief
 * Returns value of an etSTR option.
 *
 * \param[in] option Name of etSTR argument to query.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   Value of \p option.
 *
 * \p option must specify a valid argument in \p pa of the correct type.
 */
const char* opt2parg_str(const char* option, int nparg, t_pargs pa[]);

/*! \brief
 * Returns value of an etENUM option.
 *
 * \param[in] option Name of etENUM argument to query.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   Value of \p option.
 *
 * \p option must specify a valid argument in \p pa of the correct type.
 */
const char* opt2parg_enum(const char* option, int nparg, t_pargs pa[]);

/*! \brief
 * Returns whether an argument has been set.
 *
 * \param[in] option Name of argument to check.
 * \param[in] nparg  Number of elements in \p pa.
 * \param[in] pa     Array of arguments.
 * \returns   `true` if \p option has been set.
 *
 * \p option must specify a valid argument in \p pa.
 */
bool opt2parg_bSet(const char* option, int nparg, const t_pargs* pa);


/** Add option -w to view output files (must be implemented in program). */
#define PCA_CAN_VIEW (1 << 5)
/** Add option to set begin time for trajectory reading. */
#define PCA_CAN_BEGIN (1 << 6)
/** Add option to set end time for trajectory reading. */
#define PCA_CAN_END (1 << 7)
/** Add option to set time step for trajectory reading. */
#define PCA_CAN_DT (1 << 14)
/** Add all options for trajectory time control. */
#define PCA_CAN_TIME (PCA_CAN_BEGIN | PCA_CAN_END | PCA_CAN_DT)
/** Add option -tu to set time unit for output. */
#define PCA_TIME_UNIT (1 << 15)
/** Add option -deffnm to set default for all file options. */
#define PCA_CAN_SET_DEFFNM (1 << 10)
/** Do not raise a fatal error when invalid options are encountered. */
#define PCA_NOEXIT_ON_ARGS (1 << 11)
/** Don't do any special processing for ffREAD files */
#define PCA_DISABLE_INPUT_FILE_CHECKING (1 << 17)

/*! \brief
 * Parse command-line arguments.
 *
 * Some common default arguments are also recognized in addition to those
 * provided through \p pa.  The set of recognized default arguments is affected
 * by \p Flags.
 *
 * Recognized arguments are removed from the list.
 *
 * For full functionality, this function needs to be used within a function
 * that is passed to gmx_run_cmain().  It should be called as the first thing in
 * that function.  Initialization code can be executed before it, but you need
 * to be aware that if the program is executed with -h and MPI, the code before
 * parse_common_args() only executes on the main node.
 *
 * If the return value is `FALSE`, the program should return immediately (this
 * is necessary for -h and a few other cases).
 *
 * \see gmx_run_cmain().
 */
bool parse_common_args(int*               argc,
                       char*              argv[],
                       unsigned long      Flags,
                       int                nfile,
                       t_filenm           fnm[],
                       int                npargs,
                       t_pargs*           pa,
                       int                ndesc,
                       const char**       desc,
                       int                nbugs,
                       const char**       bugs,
                       gmx_output_env_t** oenv);

/*! \} */

#endif
